Eugen Fischer (5 June 1874 – 9 July 1967) was a German professor of medicine, anthropology, and eugenics, and a member of the Nazi Party. He served as director of the Kaiser Wilhelm Institute of Anthropology, Human Heredity, and Eugenics, and also served as rector of the Frederick William University of Berlin.
Fischer's ideas informed the Nuremberg Laws of 1935 which served to justify the Nazi Party's belief in German racial superiority to other "races", and especially the Jews. Adolf Hitler read Fischer's work while he was imprisoned in 1923 and he used Fischer's eugenic notions to support his vision of a pure Aryan society in his manifesto Mein Kampf (My Struggle).
After the war, Fischer completed his memoirs. It is believed that in them he lessened his role in the genocidal programme of Nazi Germany. He died in 1967.